Process and apparatus for loading extrusion presses



March 16, 1965 H. VOGTMANN 3,173,283

PROCESS AND APPARATUS FOR LOADING EXTRUSION PRESSEIS Filed Dec. 27. 1960 MAIN WINDING A AUXILARY WINDING INGOT 4 United States Patent 3,173,283 PROCESS AND APPARATUS FOR LOADING EXT RUSION PRESSES Hans Vogtmann, Bechemstrasse '11, Duisburg, Germany Filed Dec. 27, 1960, Ser. No. 78,630 9 Claims. (61. 72-270) The present invention relates to a process and apparatus for transporting a heated metal ingot from a heating station to an extrusion press and loading the ingot into a receiving chamber of the press, and more particularly to such a process and apparatus wherein the heated ingot is introduced into the receiving chamber by means of an electrical force field.

Metal ingots or billets have been introduced to loaded into the receiving chambers of extrusion presses by various methods and apparatus, most commonly by means of a mechanical or hydraulic device which places the ingot or billet coaxially with the receiving chamber of the press, whereupon the ingot is engaged by a ram or plunger which pushes the ingot into the receiving chamber and thereafter forces the heated ingot through the die.

According to the present invention the heated ingot is transported and introduced into the receiving chamber of an extrusion press in a simple and expeditious manner by heating the ingot inside an induction coil, moving the ingot together with the coil in front of the receiving chamber of the press in alignment wit-h the opening thereof and floating it by means of an electrical force field from the coil into the receiving chamber.

The induction coil is mounted on a carriage which is adapted to be moved substantially perpendicularly to the longitudinal axis of the press. The ingots remain in the induction coil where they are maintained at the desired temperature until the preceding pressing operation has been completed, whereupon a new ingot is loaded into the receiving chamber. The temperature of the ingot is controlled by means of a thermostat and maintained at the desired value by a cycling of the current in the induction coil.

It has now been discovered that when there exists an unbalance of the electromagnetic field Within an induction coil relative to the ingot which is disposed preferably axially asymmetrically with reference to the geometrical center of the electrical field, that this tends to exert a force on the ingot which may generate a substantial electrodynamic impetus.

According to the present invention the induction coil is mounted movably and is employed to introduce the ingot directly from the coil into the extrusion press. In this novel method, the ingot which is placed into the induction coil for heating purposes, is moved on a carriage together with the induction coil to the center of an extrusion press and is axially moved by the force generated due to an asymmetrical arrangement of the electromagnetic field in a manner that it floats freely into the bore of the receiving chamber of the press. The force of the electromagnetic field generated in the induction coil will move the billet lengthwise or axially of the coil, as it is well known in the art and as indicated for example in US. Patents 2,003,855-Fredrickson and 2,910,565Osborn. The required temperature control circuit of the inductive heating means for heating the ingot, usually including a thermostat, is supplebeen moved together with the heated ingot to the center of the press, and the receiving chamber is ready to be loaded, the ingot to be introduced is moved with increasing speed by means of short periodic energization of the induction-field in a jolt-like manner in the direction of the bore of the receiving chamber. An abutment or other suitable stop means retains the ingot within the induction coil while it is being heated.

The above described process may be modified by placing the ingot itself asymmetrically into the induction field and securing the ingot against the impelling force exerted thereon by the magnetic field by providing an abutment of suitable dimensions and construction. This abutment is fixed to the coil, and is removed at the time when the ingot has been moved together with the induction coil to the center of the press and is ready to be mented by an additional circuit arrangement associated t loaded into the receiving chamber of the press by the electromagnetic force exerted thereon.

In a further modification of the present invention the induction coil may be provided with an auxiliary winding which is disconnected while the ingot is being heated. In this case the ingot is disposed symmetrically with reference to the center of the electrical field. For this type of arrangement the induction field may be connected during the period that the ingot is being moved into the center of the press. At the time when the ingot is to be loaded into the receiving chamber of the press, the auxiliary winding is connected, which has the efiect of creating an unbalance or asymmetry of the combined electrical force fields with reference to the geometrical center of the ingot, which is essential to exert a propelling force on the ingot. With this arrangement it is not necessary to provide an abutment means for retaining the ingot in position during the heating period.

The installation for transporting the ingot is positioned in the proximity of the press. As indicated above, the induction coil is movably mounted on a carriage which is slidable on a guide track. As soon as the carriage has been returned from a completed loading operation back to its starting position, the ingot, which is disposed in front of the opening of the induction coil in juxtaposed relation to the guide track and carriage, is inserted into the coil by means of a plunger which is actuated automatically by a suitable electrical switching arrangement. As soon as the ingot is properly located inside the coil, the induction circuit is automatically connected and the ingot is heated to the desired temperature, which is maintained constant by automatically opening and closing the circuit. In this arrangement the thermostatically controlled temperature may be so adjusted that during brief transporting period of the induction coil from the heating station to the receiving chamber of the press, no undesirable temperature variations take place.

An essential advantage of the method and apparatus according to the invention resides in the fact that the press for extruding metal rods or tubes may be built very compactly and of reduced length. With this arrangement the space between the front face of the receiving chamber and the ram in the retracted position is required to be only slightly larger than is necessary to accommodate the longitudinal dimension of the ingot proper. The inductive coil which is moved into this space is only slightly longer than the metal ingot.

According to an additional feature of the invention, the induction coil for heating the ingots may be split longitudinally and may thus be opened by folding the two halves apart in order to allow easy access to the coil and permit a quick removal of the ingot from the coil. In case of ditiiculty such induction coils are known in the prior art, for example in US. Patent 2,600,034.

Additional features and details of the invention will become apparent from the following description when ta taken in connection with the accompanying drawing in which an embodiment of the invention is shown by way of example only.

In the drawing:

FIGURE 1 is a plan view of the apparatus of the invention in the starting position in which an ingot is disposed in the induction coil.

FIGURE 2 is a plan view according to FIGURE 1 with the induction coil and ingot'located centrally of the press.

FIGURE 3 is another plan view according to FIGURE 1 in which the press is shown just prior to the start of the extrusion process and with a new ingot about to be introduced into the induction coil.

FIGURE 4 is a circuit diagram of a modified form of the invention utilizing a main winding and an auxiliary winding.

Referring more particularly to FIGURE 1 of the drawing, numerals 1a, 1b and 1c designate three metal ingots arranged in a supply installation 2 which may suitably be an inclined ramp, and which is adapted to insert the ingots by means of a plunger 3 into an induction coil 4. As shown in this figure, ingot 1a has been introduced by means of plunger 3 into induction coil 4 into engagement with an abutment 5, and the subsequent ingot lb has been moved into position to be inserted. The induction coil is arranged on a carriage 6 which is movably mounted on guide rails 7. The details of the carriage structure are not shown or described in detail, as they are not a part of the present invention and are not necessary for a proper understanding of the novel features of this invention.

Referring more particularly to FIGURE 2, the ram 8 of the extrusion press is pulled away from the receiving chamber 9 of the press just far enough to provide enough room so that the induction coil 4 may be moved into this space in front of the entrance to the receiving chamber 9 in axial alignment with the bore 9. While the ingot is being moved to the center of the extrusion press, the subsequent ingot 1b, which has been maintained stationary by an abutment or similar retaining means, is released and moved in front of the plunger 3.

Referring now more particularly to FIGURE 3, the heated ingot 'la is shown after it has been deposited in the bore of the receiving chamber 9, and theram 8 of the extrusion press has been advanced to the position where it is in engagement with the ingot just prior to the start of the extrusion of the ingot. In the arrangement shown in FIGURE 3, the carriage 6 supporting the induction coil 4 has been returned toits starting position. The same steps may now be repeated wherein the plunger 3 moves the ingot 1b, which is already in position in front of the piunger, into the opening in the induction coil 4-, while the subsequent block 1c is held back in its starting position by a suitable abutment means. As already described above, the ingot is inserted into the induction coil, is heated while the preceding ingot is being extruded in the press, then moved together with the coil by means of'the carriage 6 in front of the opening of the receiving chamber of the press, introduced into the receivin chamber by applying a magnetic field asymmetrically to the ingot and is extruded by means of a ram through a die provided at the opposite end of the receiving chamber.

As pointed out above the invention may be modified, 6 as best seen in FIGURE 4, wherein the induction coilis made without departing from the spirit and scope of the invention. It is therefore apparent that the foregoing description is intended only as an illustration of the invention rather than limitation of the invention.

What is claimed is:

1. Apparatus for loading a metal ingot into a receiving chamber of an extrusion press comprising a movably mounted electrical induction coil having a plurality of windings, means for inserting a metal ingot into said induction coil, means for energizing at least a first winding in said coil to heat said ingot, means for moving said induction coil containing said'heated ingot into said extrusion press in axial alignment with the receiving chamber, means for exerting a propelling force on said ingot to float said ingot into said receiving chamber, said force exerting means including the means for energizin said first winding and an additional winding to produce in a known manner a magnetic field oriented asymmetrically relative to said ingot.

2. Apparatus as defined in claim 1 wherein said induction coil is energized intermittently to propel said ingot with increasing speed into the bore of said receiving chamber.

3. Apparatus for loading a metal ingot into a receiving chamber of an extrusion press comprising a movably mounted electrical induction coil, said induction coil comprising a main winding and an auxiliary winding, means for inserting a metal ingot into said coil, means for energizing said main winding of said coil to thereby heat said ingot, means for moving said coil containing said heated ingot into said extrusion press in axial alignment with the bore of said receiving chamber, means for exerting a propelling force on said ingot to float said ingot into said receiving chamber, said force exerting means including the means for energizing said main winding and said auxiliary winding to produce in a known manner a magnetic field oriented asymmetrically relative to said ingot.

4. Apparatus as defined in claim 3 wherein said auxiliary winding is energized after said metal ingot has been moved into axial alignment with said receiving chamber.

5. The method of loading a metal ingot into the bore of a receiving chamber of an extrusion press comprising locating the ingot into a movably mounted induction coil so as to be oriented asymmetrically relative to the magnetic field adapted to be generated in said induction coil, heating the ingot to a predetermined temperature, restraining the ingot from movement relative to the'coil, moving the induction coil and the ingot together into axial alignment with the bore of the receiving chamber, releasing the ingot from the coil and energizing the coil in a known manner to generate a magnetic field oriented asymmetrically to the ingot to propel the ingot into the bore of the receiving chamber.

6. The method defined in claim 5 wherein the coil is energized intermittently to generate electrical impulses adapted to propel the ingot with increasing force into the bore of the receiving chamber.

7. The method of loading a metal ingot into the bore of a receiving chamber of an extrusion press comprising inserting the ingot into a movably mounted induction coil having a plurality of windings, heating the ingot in the induction coil to a predetermined temperature by means of at leastone of said windings, movingthe induction coil and the ingot together into the extrusion press in alignment with the bore of the receiving chamber, energizing at least one additional winding in a .known manner to generate a combined magnetic field oriented asymmetrically relative to the metal ingot to thereby propel said ingot into the bore of the receiving chamber.

8. The method of loading a metal ingot into the bore of a receiving chamber of an extrusion press as defined in claim 7 further including the step of locating the ingot in t e mo eably mounted induction coil so as to be oriented symmetrically relative to the magnetic field adapted to be generated in said induction coil.

9. The method of loading a metal ingot into the bore of a receiving chamber of an extrusion press as defined in claim 7 further including the step of locating the ingot in the moveably mounted induction coil so as to be oriented asymmetrically relative to the magnetic field adapted to be generated in said indutcion coil.

896,684 Benjamin Aug. 18, 1908 Noble Dec. 3, Stout Sept. 15, Fredrickson June 4, Weingart June 10, Garner et a1. Feb. 14, Leber July 14, Guyer et a1. Sept. 22, Osborn et a1. Oct. 27, Baker May 3,

FOREIGN PATENTS Australia Dec. 20, Great Britain Apr. 4, 

1. APPARATUS FOR LOADING A METAL INGOT INTO A RECEIVING CHAMBER OF AN EXTRUSION PRESS COMPRISING A MOVABLY MOUNTED ELECTRICAL INDUCTION COIL HAVING A PLURALITY OF WINDINGS, MEANS FOR INSERTING A METAL INGOT INTO SAID INDUCTION COIL, MEANS FOR ENERGIZING AT LEAST A FIRST WINDING IN SAID COIL TO HEAT SAID INGOT, MEANS FOR MOVING SAID INDUCTION COIL CONTAINING SAID HEATED INGOT INTO SAID EXTRUSION PRESS IN AXIAL ALIGNMENT WITH THE RECEIVING CHAMBER, MEANS FOR EXERTING A PROPELLING FORCE ON SAID INGO TO FLOAT SAID INGOT INTO SAID RECEIVING CHAMBER, SAID FORCE EXERTING MEANS INCLUDING THE MEANS FOR ENERGIZING SAID FIRST WINDING AND AN ADDITIONAL WINDING TO PRODUCE IN A KNOWN MANNER A MAGNETIC FIELD ORIENTED ASYMMETRICALLY RELATIVE TO SAID INGOT. 